Problem: Combine like terms to simplify the expression: ${\dfrac{2}{5}k-\dfrac35+\dfrac{1}{10}k}$
Solution: Combine the $\text{{coefficients}}$ of the $k$ terms. $\phantom{=}{{\dfrac{2}{5}}k-\dfrac35+{\dfrac{1}{10}}k}$ $=\left({\dfrac{2}{5}}+{\dfrac{1}{10}}\right)\cdot k-\dfrac35$ $=\left({\dfrac{4}{10}}+{\dfrac{1}{10}}\right)\cdot k-\dfrac35$ $=\left({\dfrac{5}{10}}\right)\cdot k-\dfrac35$ $=\left({{\dfrac{1}{2}}}\right)\cdot k-\dfrac35$ $=\dfrac12k-\dfrac35$ The simplified expression is $\dfrac12k-\dfrac35$